title: Individual fascicles of the paraspinal muscles are activated by discrete cortical networks in humans.
abstract: OBJECTIVE
  To investigate whether functional specificity in different fascicles of the paraspinal muscles is associated with discrete organisation within the motor cortex.
  
  
  METHODS
  In 11 healthy volunteers, electromyographic (EMG) activity was recorded bilaterally using fine-wire intramuscular electrodes from the short and deep fibres of multifidus (DM) at L4, and the longer and more superficial fibres of longissimus erector spinae (LES) at L4 and L1. Surface electrodes were also placed over the right LES at L4 and L1. Organisation at the motor cortex associated with motor excitation was investigated using transcranial magnetic stimulation (TMS).
  
  
  RESULTS
  The results showed that motor cortical representation for DM was located posteriorly to that for LES. TMS maps from surface recordings of LES showed two optimal sites, which were located in proximity to the sites for DM and LES from intramuscular recordings.
  
  
  CONCLUSIONS
  Different fascicles of the paraspinal muscles are organised and thus could be controlled by discrete neuronal networks within the motor cortex. Further, TMS mapping from surface recordings of paraspinal muscles may be confounded by cross-talk from multiple underlying fascicles.
  
  
  CONCLUSIONS
  Discrete organisation at the motor cortex appears consistent with differential activation of different fascicles of the paraspinal muscles with function.
authors.affiliation: Centre for Clinical Research Excellence in Spinal Pain, Injury and Health, School of Health and Rehabilitation Sciences, The University of Queensland, Brisbane, Australia.
authors.forename: Henry
authors.initials: H
authors.lastname: Tsao
authors.forename: Lieven
authors.initials: L
authors.lastname: Danneels
authors.forename: Paul W
authors.initials: PW
authors.lastname: Hodges
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001931:Brain Mapping; D004558:Electric Stimulation / Q000379:methods; D004576:Electromyography / Q000379:methods; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D009434:Neural Pathways / Q000502:physiology; D011930:Reaction Time; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult